The sinus augmentation surgeries will be performed by the attending surgeons at the Oral and Maxillofacial department, according to a unified protocol: a pre-op chlorhexidine 2% rinse, local anesthesia with Lidocaine 2% with adrenalin 1:100000, elevation of a mucoperiosteal flap to expose the lateral wall of the sinus, performing an access window in the bony wall and lifting the sinus membrane, augmentation of the cavity using a xenogeneic and /or allogeneic bone graft substitute and a collagen membrane, placement of dental implants if feasible and suturing of the flap.